Generally, washing machines include a pulsator washing machine in which a drum is vertically erected, a drum washing machine in which a drum is horizontally laid, a drying and washing machine having drying and washing functions, and a drying machine having only a drying function.
Among the washing machines, the pulsator washing machine, the drum washing machine, and the drying and washing machine perform a washing operation using washing water.
In the washing operation, a large amount of washing water is required. Accordingly, various attempts to minimize the amount of the washing water used to wash laundry are currently being investigated.
For this reason, a steam generator is provided. The steam generator assists the washing operation so that the washing operation is performed using a small amount of washing water.
Hereinafter, with reference to FIGS. 1 and 2, a conventional steam generator for a washing machine will be described in detail.
As shown in FIGS. 1 and 2, the conventional steam generator comprises a case 1, and a heater 2.
The case 1 defines the external appearance of the steam generator, forms a space for storing water required to generate steam, and comprises an upper case 11 forming the upper portion of the case 1 and a lower case 12 forming the lower portion of the case 1.
A water supply pipe 1a connected to a water supply channel (not shown) of the washing machine is formed at one side of the case 1, and a steam discharge pipe 1b connected to a steam supply pipe (not shown) for supplying steam generated in the case 1 by evaporation to the inside of a drum of the washing machine is formed at the other side of the case 1.
The heater 2 is installed in the horizontal direction in the lower portion of the case 1.
The heater 2 is a sheath heater, and two terminals of the heater 2 are exposed from one side of the case 1 to the outside.
The heater 2 serves to generate heat to evaporate water stored in the case 1.
Accordingly, when the steam generator is operated, the heater 2 generates heat, and thus evaporates water stored in the case 1. Steam obtained by the evaporation of the water is discharged to the outside through the steam discharge pipe 1b, and is supplied to the inside of a drum (not shown) of the washing machine, thereby performing various operations using the steam.
The selective generation of heat from the heater 2 and the supply of water into the case 1 in the above conventional steam generator must be performed only at a point of time when these operations are possible.
Here, the point of time means a state in which a sufficient amount of water is supplied to the inside of the case 1.
The conventional steam generator does not have a separate device for correctly measuring the supply amount of water in the steam generator according to respective states, but only has a water level sensor for detecting whether or not water exists in the steam generator.
The washing machine having the conventional steam generator is operated when water exists in the steam generator regard lower of the supply amount of the water in the steam generator. Accordingly, during the operation of the steam generator, a lack of water occurs and the heater 2 is exposed to external air.
Thereby, the temperature in the case 1 rapidly increases, and the case 1 is deformed and contacts the heater 2, thus causing danger of a fire.